:root {
    --primary-color: #3498db;
    --secondary-color: #ecf0f1;
    --text-color: #333;
    --bg-color: #fff;
    --sidebar-width: 250px;
}

body,
html {
    margin: 0;
    padding: 0;
    font-family: 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    height: 100%;
}

.chat-container {
    display: flex;
    height: 100vh;
}

.sidebar {
    width: var(--sidebar-width);
    background-color: var(--secondary-color);
    display: flex;
    flex-direction: column;
    border-right: 1px solid #ddd;
}

.sidebar-header {
    padding: 20px;
    border-bottom: 1px solid #ddd;
}

.chat-list {
    flex-grow: 1;
    overflow-y: auto;
}

.chat-item {
    padding: 15px 20px;
    cursor: pointer;
    display: flex;
    align-items: center;
    border-bottom: 1px solid #ddd;
}

.chat-item.active {
    background-color: #e0e0e0;
}

.chat-item i {
    margin-right: 10px;
}

.chat-time {
    font-size: 0.8em;
    color: #777;
    margin-left: auto;
}

.sidebar-footer {
    padding: 20px;
    display: flex;
    justify-content: space-between;
}

.sidebar-footer button {
    background: none;
    border: none;
    font-size: 1.2em;
    cursor: pointer;
}

.chat-main {
    flex-grow: 1;
    display: flex;
    flex-direction: column;
}

.chat-header {
    padding: 20px;
    border-bottom: 1px solid #ddd;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.chat-header h2 {
    margin: 0;
}

.chat-header h2 span {
    font-size: 0.8em;
    color: #777;
}

.header-actions button {
    background: none;
    border: none;
    font-size: 1.2em;
    margin-left: 15px;
    cursor: pointer;
}

.chat-messages {
    flex-grow: 1;
    overflow-y: auto;
    padding: 20px;
}

.chat-footer {
    padding: 20px;
    border-top: 1px solid #e0e0e0;
}

.input-container {
    display: flex;
    align-items: center;
    max-width: 800px;
    margin: 0 auto;
    /* 居中显示 */
}

#user-input {
    flex-grow: 1;
    border: 1px solid #ddd;
    border-radius: 20px;
    padding: 10px 15px;
    font-size: 16px;
    resize: none;
    max-height: 100px;
    /* 限制最大高度 */
    overflow-y: auto;
    /* 如果内容超出，显示滚动条 */
}

#send-btn {
    background-color: #3498db;
    /* 使用蓝色，您可以根据需要调整 */
    color: white;
    border: none;
    border-radius: 50%;
    width: 40px;
    height: 40px;
    margin-left: 10px;
    cursor: pointer;
    display: flex;
    justify-content: center;
    align-items: center;
}

#send-btn:hover {
    background-color: #2980b9;
    /* 鼠标悬停时的颜色 */
}

#send-btn i {
    font-size: 18px;
}